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-----Original
Message----- Adam Britton
wrote: >Although
I don't believe it's particularly important for crocs, it should be I think that
this is very important for all crocodilians. (Theropod) Dinosaurs did not have
this feature, instead, they had spaces between their maxillae (which were
"V" shaped) and mandibles (which were "U" shaped).
Theropods would have a large gap between the lower jaw and the upper.
Therefore, lips would be required in dinosaurs to prevent desiccation.<< What?
Please explain the “V”shape of the maxillae? The
maxillae don’t touch each other, do you mean the premaxilae? No, not all
theropods had the “U” shaped dentaries (or in other words, where the dentaries
join each other). Tyrannosaurus has a “U” shaped prermaxillae and a “V” Shaped
dentary. There IS a HUGE gap between the lower and upper jaws when the mouth
was closed. When you add the width of the upper teeth (about 5 cm) to the width
of the gap, you’d have to have a gap between the outside of the dentary to the
inside of the upper lip of about 10 cm!!! How would they be able to sustain
that gap? In order to have lips, you
need both upper and lower lips, which from, guess what, my research, yep I did
research on it, theropods didn’t have lips. There is no reason why theropods
couldn’t have been able to keep a ‘seal’ like a crocodile with the mouth
closed. The ‘lipless’ croc’s can and do, seal off their mouths. When they are
lying out in the sun they can and do (at times) keep their mouths closed and
keep the moisture in the mouth. Tracy L. Ford P. O. Box 1171 Poway Ca
92074 |